fix: remove 7 unused variables in widgets and Homepage components

Cleaned up unused imports, parameters, and variables:
- DiskWidget.tsx: removed metricsHistory parameter
- FileManagerContextMenu.tsx: removed ExternalLink import
- Homepage.tsx: removed useTranslation import
- HomepageAlertManager.tsx: removed loading variable
- HomepageAuth.tsx: removed setCookie import (Desktop & Mobile)
- HompageUpdateLog.tsx: removed err parameter

Reduced lint errors from 222 to 216 (6 errors fixed)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/ui/Mobile/Homepage/HomepageAuth.tsx

@@ -19,7 +19,6 @@ import {
   completePasswordReset,
   getOIDCAuthorizeUrl,
   verifyTOTPLogin,
-  setCookie,
   getCookie,
   logoutUser,
   isElectron,